Building your own wireless network


Here are some notes about building a wireless network for use by the community around you. The technology is used to provide high speed, permanently on connectivity between the members of your community. In the case of the network we built in our village we have a measured throughput of 6 Mbit/sec. This is more than fast enough for applications such as IP telephony, video conferencing, multi-player network games or streaming MP3 from a central server. A secondary function of the network is to provide access to the Internet as anyone connected to the network.

All this can be had for a very small amount of money and some money by using standard off the shelf wireless ethernet equipment using the 802.11 family of standards.

The notes given here I hope will provide the necessary knowledge for a reasonably technically motivated individual person or group to get going and who to talk to when you get stuck.

Social and legal considerations

The wireless network equipment we are using requires no license to operate as it uses the license free 2.4GHz band. This is not to say that use of this band is without restriction in the UK. The conditions of use of this band are that you will not use it 'by way of business'. This means that if you are a business then you cannot offer services using this technology even if you are giving it away for free. An example of this would be that a coffee shop cannot offer wireless network services even for free as this would be 'by way of business'. The rules are different in other countries.

The regulations however do not stop you as an individual from putting up an access point that can be used by the people around you. It also does not prevent you from forming a club or society.

Use of the band is also subject to restrictions on the maximum signal strength and equipment needs to be certified compliant to the relevant European standards covering this equipment.

For the curious, adventurous or cash poor we present some antennas that you can build yourself for just a few pounds. Note however that none of these designs have any certification and some of the designs provide very high gain such that when used with a standard network card will produce a higher signal level than that allowed.


A good antenna placed correctly is essential if you are to get any distance. The network cards have built in antennas. Due to the space requirements and the placement of these antennas you will only get a range of about 100m outdoors. Indoors it is likely to be much worse than this. In my house I am lucky to be able to get a signal two rooms away. Such a range is obviously no good for reaching out to your neighborhood and to get a decent range you need an external antenna mounted such that it has line of sight to those that you wish to reach. When choosing a place for your antenna remember that we are dealing with microwaves. These do not like passing though buildings and trees.

In order to be able to use an external antenna you need to have a card with an external antenna connector such as the Lucent/Augre/Orinoco card (they keep changing their brand name). This has a very very small proprietary connector. Into this you plug a 'pigtail' lead. This is a short bit of cable with the proprietary connector on one and and a standard N type connector on the other into which you can connect your thick antenna cable. These pigtail leads are rather expensive and difficult to source from other manufacturers due to the proprietary connector.

If you are going to mount the antenna somewhere high up a length of coax cable is required to get the signal to the antenna. You cannot just use any old bit of coax like TV cable as the attenuation at 2.4 GHz is just too high. You will need something better like LMR400 which is expensive and not carried by your local electronics store. I had to resort to buying original equipment cable to get up the chimney to my antenna.

Broadly, antennas come in two varieties, directional and omnidirectional. Directional antennas in general have a higher gain and are used for point to point links. Omnidirectional antennas are used to broadcast the signal 360 degrees around the antenna.

High gain directional helical antenna
Testing helical antenna

Mathematical modeling of normal mode helix antenna (omnidirectional)


Thoughts on authentication

Node building instructions

Howto build a node from an old PC and a copy of RedHat Linux 7.1. This document is in PDF.

Moreton Morrell network

The network that we built in Moreton Morrell is currently a proof of concept that has been running now for several months without problem.

Our network consists of two nodes on each side of the village about 350m apart connected with directional antennas at each end. Currently this is used to connect the networks at my house and a friends house. The next phase of the project is to tell the community about the trial to see what response we get. If favorable then we will extend the network. It is hoped to enlist some of the teenagers in the village to provide technical help to users wanting to connect to the network.

Currently the network is connected to the Internet by an ISDN connection. This is adequate for the two houses currently on the network but something bigger will be needed if the network grows. Unfortunately there is no ADSL available in our village. One possibility is to extend the network across country and link up with Leamington Spa where ADSL is available. This however will not be easy as several hops will be required to get there as there are a series of hills between us and Leamington. A second line of attack is to approach the local college with which we have direct line of sight and could be done in one hop. Neither of these approaches have had any work done on them and won't until we ascertain a good take-up in the village.